It is known to bind or bond electrical wires and not to separate them from one another because a plurality of separated electrical wires extending between a pair of connectors in a harness make the harness difficult to handle due to entangling of the wires and the connectors of one harness or a plurality of harnesses.
The simplest technique to avoid the above problem is to bind a plurality of wires by manually taping around the wires of the assembled harness at desired locations. It is effective to bind at any desired location but a disadvantage is the manual operation which is not suited for quantity production. Also, automatic taping requires an additional taping machine separated from the wire harness making machine, thereby increasing cost, space and harness making steps.
In view of the above, it is proposed to use fused or intercoupled wires for making a harness. Such prior art technologies can be classified into two groups; one for using partly fused wires as disclosed in Japanese Patent Publication No. 96611/86 and the other for using completely fused wires as set forth in Japanese Patent No. 14708/92.
In case of using wires partly fused in advance, the pitch of the fused wires must be converted to be equal to the pitch of contacts of the connector before the wires are insulation displaced to the connector. It is typical to insulation displace at the portions of the wires where not fused to one another. However, a slitter to separate the fused wires is required so as to insulation displace at any location, especially when the harness length is preferably changed.
It is also true to use a slitter and/or a pitch converter to convert the wire pitch to the insulation displacing pitch when fully fused wires are to be used. Another disadvantage of using such fused wires is the wires are less flexible which is inconvenient in handling.
As described hereinbefore, in case of making a harness using partly or fully fused wires, there is a need for pitch conversion from the wire pitch to the insulation displacing pitch which often requires a slitting operation of the wires at the fused portion.
In case of using wires already fused in part or along their entire length, there arises the need for a device to fuse and bind the wires in advance separated from the harness making machine and also for a pitch converter and a slitter, thereby making the harness making apparatus complicated. Additionally, slitting the cut ends of a plurality of wires to convert the wire pitch into the insulation displacing pitch accompanies spreading the wire ends, thereby shortening the outer wires as compared with the central wires in the longitudinal direction. This results in improper insulation displacing the wires to a connector.
In view of the above problems, it is an object of the present invention to provide a harness making apparatus capable of continuously performing the steps of insulation displacing a plurality of wires to a connector and of fusing to couple the wires at desired locations.